Many processes have been taught in the prior art for forming a covered article such as an automobile seat cushion. For example it has been proposed to vacuum form an outside cover from a sheet of vinyl and then to react a foamable composition within the interior volume of the cover to form the resilient portion of the seat cushion. One difficulty encountered with such a vacuum forming method is that only a special vinyl material may be used in the process because of the depth of the draw on the material in the forming operation. The vinyl material used in the process is relatively expensive also because the material must be heat resistant. Thus a seat cushion made with a vacuum formed cover and a foamed interior has its drawbacks.
Another method for forming a covered article such as an automobile seat cushion is one wherein the cover of the article is formed in an injection molding operation. The mold and molding press for such a molding operation are very expensive. Also after a cover is injection molded, it has to be painted in order to obtain the proper color on the exterior surface thereof. Thus, forming a seat cushion by manufacturing the exterior cover in an injection molding operation and thereafter reacting a foamable composition therewith also has its drawbacks.
Still another method proposed for forming a covered article such as an automobile seat cushion is one wherein a self-skinning foam is employed. In this case, the foamable composition is reacted in a mold and it produces its own relatively thin exterior skin and a porous resilient interior. The difficulty with this process is that the weight per unit volume is higher than covered articles produced by other methods. Also the finished seat cushion is relatively hard and does not give the seating comfort desired. This type of construction also has to be painted in order to produce a finished article. Also, as another drawback to this process no cloth or vinyl material can be utilized as the foam develops its own exterior skin.